Between 1885 and 1927, the observatory employed about 80 women who studied glass plate photographs of the stars, many of whom made major discoveries. They found galaxies and nebulas and created methods to measure distance in space. In the late 1800s, they were famous: newspapers wrote about them and they published scientific papers under their own names, only to be virtually forgotten during the next century. But a recent discovery of thousands of pages of their calculations by a modern group of women working in the very same space has spurred new interest in their legacy.

Surrounded by steel cabinets stuffed with hundreds of thousands of plate glass photographs of the sky, curator Lindsay Smith Zrull shows off the best of the collection.

“I have initials but I have not yet identified whose initials these are,” Smith Zrull says, pointing at a paper-sized glass plate crowded with notes taken in four different colors. “One of these days, I’m going to figure out who M.E.M. is.”